Water vole and otter surveys
Once common and widespread throughout the British Isles, water voles and otters have experienced reductions in population size and range throughout the last century. Water voles have declined mainly due to habitat loss, intensification of agriculture and predation by feral American mink, whereas otters have declined due to unsympathetic land management and the reduction in the quality of our watercourses. Water voles and otters now receive legal protection from harm and disturbance, and their habitats are protected from damage and destruction. Surveys for these species may be required where development is likely to affect freshwater habitats, including streams and rivers.
Surveys to confirm the presence or likely absence of water voles and otters from your site can usually be undertaken at the same time. Best practice guidelines state that water vole surveys should involve a systematic search of habitats within 2m of watercourses within your site to look for burrows, latrines, footprints, feeding stations, pathways through vegetation and water vole sightings (Strachan et al, 2011). Otters are a highly mobile species and therefore all watercourses within the site and surrounding area should be searched for signs of their presence, including tracks, feeding remains, spraints (otter dung), holts (underground dens) and couches (above ground resting sites). Alongside searching for signs of activity, an assessment of the habitats present should also be made, including details of bank material, composition of marginal vegetation, degree of shading, presence of pollution, and water depth and velocity.
Should water voles or otters be found to be present within the site then appropriate measures may need to be put in place to allow the development to progress. See our water vole and otter mitigation page for more information.